Professor Stephen Hawking has recently published a new theory that details how black holes are able to store information.
The paper attempts to solve a famous black hole question, the information loss paradox. We know nothing can escape a black hole, not even light itself, so any information on what a black hole has consumed should also be lost.
The problem here is that it suggests that all black holes are essentially identical, and if you believed this theory up until now, none of them would be able to contain any information on what happened in their history. To balance this, this paper proposes a “hair” theory. The hair theory suggests that ripples in space time could store information at the event horizon.
This paper gives an explicit description of soft hair in terms of soft gravitons or photons on the black hole horizon.
The hairs are said to be individual rays of light moving away from the black hole that get frozen at the event horizon. They are oddities in space time that could contain information on the black hole’s past.
There’s this symmetry of a black hole that we all knew about in which you move uniformly forward and backward in time along all of the light rays. But there’s another symmetry, which is the new thing in this paper (though various forms of it have been discussed elsewhere). It’s a symmetry in which the individual light rays are moved up and down. See, individual light rays can’t talk to each other – if you’re riding on a light ray, causality prevents you from talking to somebody riding on an adjacent light ray. So these light rays are not tethered together. You can slide them up and down relative to one another. That sliding is called a super-translation.
Andrew Strominger, one of Hawking’s co-authors
Stephen Hawkings and his co-authors are quite interested in particles with zero energy known as soft particles. These particles lie at the event horizon, and when other particles are ejected they can pick up information on their way into the universe. This process is known as Hawking radiation.
When the paper was first presented, it was criticized as being “chatoic and useless”. But in time it did resolve the information loss paradox while identifying that all black holes are unique. For now, this paper remains a theory, but the “hair vs. no hair” debate is on. At the moment it remains a highly intriguing proposal on solving a long standing paradox for particle Physicists world-wide.
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